hey all, I have a few sites with accent air heat pumps for swimming pool heating but there buckets of SHT and keep failing on the heat exchangers due to the plastic outer deforming from heat and melting over time.

any one work on thease and had the same issue??
can you use the daikin altherma units for this application as I need a -10 rating as it snows here...

cheers
PS if this is posted in the wrong section please advise